“We have decided to put €20 billion into a special (state) fund in order to be able to support all those companies which might need it,” Le Maire said on Europe 1 radio.
The funds will be included in a new budget plan due to be submitted to ministers next week.
France, like all its peers, is struggling to limit the damage to its economy caused by a strict coronavirus lockdown which is likely to be extended by at least two weeks to the end of April.
“As regards Air France, we are ready, when the time comes… to intervene,” Le Maire said.
Separately, the head of automaker Renault, Jean-Dominique Senard, said his company would hope to get state guaranteed bank loans worth four to five billion euros to help it through the crisis.
“We are working on ideas for bank loans which will be guaranteed by the state and which, one day or another, would be repaid, that is we would not weigh on the state's finances,” Senard told RTL radio.
“I am absolutely certain that that should allow us to get through this difficult period,” he added.
Asked about the amount, Senard said any loans were likely to be around that size but stressed it was too early to talk numbers.
Senard also ruled out any prospect of renationalising Renault, in which the French government holds a 15 percent stake.